"Safe" shotgun shot.
An example of the element Bismuth

"Safe" shotgun shot.
These are pellets from a seven pound bottle of shot sold for "reloading", which is the process of making your own ammunition by combining cartridge cases (new or refurbished), primer, propellant and shot. Lead shot and bullets have been banned in many areas because they poison the environment. The main substitute materials are steel, bismuth and tungsten. Bismuth is very similar to lead in density, melting point, hardness, etc, so it makes a pretty direct replacement, unlike tungsten which is much denser, much harder, and completely impossible to melt under any kind of reasonable conditions.

Unlike lead, bismuth is highly crystalline and brittle: This means that solid bullets made of bismuth shatter into dust on impact with hard surfaces, which in turn means that bismuth ammunition is sold as safer for use in urban environments or other places where ricochet would be bad. Safe being a relative term in connection with bullets.